“People ask me about Starlin,” Renteria said. “I watch him from the other side and I go: ‘Gosh, what a tremendously gifted athlete.’ First of all, I got to get to know him as a person and I have to figure out what it is that moves him.

“He’s a wonderful kid. I actually was able to speak to him at length – he’s one of the first guys that I called – and he’s willing to do anything we ask him to do.”

Cubs executives already knew Renteria as the San Diego Padres bench coach, and he impressed them with an upbeat attitude, a high energy level and the ability to speak Spanish.

But Renteria is supposed to give Castro some “tough love.” After a lost season of “mixed messages,” the Cubs have to rewire their two-time All-Star shortstop.

“I know people talk about him losing focus and maybe having bad at-bats and things of that nature,” Renteria said. “We have to address those things. Sometimes (we) don’t want to have a conversation or maybe we don’t like the answer we’re going to get.

“But the reality is you have to (communicate). The only way you can improve things is to converse and try to put at least a plan (in place), or an idea of how they can move forward. And I think that’s one of the things we’re going to have to do as teachers.”

In the first year of a $60 million extension, Castro hit .245 with a .631 OPS and committed 22 errors. He will be 24 next season, when elite shortstop prospect Javier Baez should be banging on the door at Iowa.

“At some point, creating options and creating versatility is always a good thing,” team president Theo Epstein said. “In Javy’s case, he’s got a tremendous combination of instincts and athleticism that makes us think that he’ll be a natural at being able to play other positions.

“In fact, if you read his amateur scouting reports, people say this guy could play every position on the field – including catcher. He could go out to the outfield with no problem. He could play all around the infield and we’ve seen that in glimpses, whether it’s shagging flyballs or just the internal clock he has, the instincts he has for the game. I think it’ll be an easy transition for him – if and when that time comes.”

During his age-20 season, Baez generated 37 homers and 111 RBI in 130 games split between advanced Class-A Daytona and Double-A Tennessee. He will also inevitably experience the same ups and downs as Castro.

“He hasn’t even reached Triple-A yet, so there’s plenty of time to do it,” Epstein said. “You don’t want to take shortstop away from a kid, because once you move off shortstop, it’s really hard to move back. There may be a time in the future where he moves on a permanent basis. There may be a time where he moves just to give him versatility.”

In the end, how Renteria handles Baez, Castro and this wave of young players will be a huge part of the job.